/Engine/Source/Runtime/Experimental/ChaosCore/Public/Chaos/ImplicitQRSVD.h
3X3 version of dRdF indexing of diff: dRdF[9*(i*3+j)+(m*3+n)] = dR.GetAt(m, n) /dF.GetAt (i, j):
namespace Chaos { template<class T> void Chaos::dRdFCorotated ( const [PMatrix](API\Runtime\Chaos\Chaos\PMatrix)< T, 3, 3 > & F, [TVector](API\Runtime\Chaos\Chaos\TVector)< T, 81 > & dRdF ) }